Hydrocarbon polymers which contain reactive functional groups are known in the art. For example, Japanese (Kokai) 7-102017 to Kanegafuchi Chemical Industry discloses the preparation of various polymers having terminal unsaturation by reacting of the corresponding hydroxyl-terminated polymer with a compound selected from an allyl halide, an acrylic acid, an oxirane ring-containing compound having carbon-carbon double bonds or a compound containing an isocyanate group and carbon-carbon double bonds in its molecule. The starting polymer, which must contain at least 1.1 hydroxyl groups per molecule, can be prepared from by a chain scission of the hydrocarbon polymer chain by reaction with ozone followed by reduction with lithium aluminum hydride, for example. This method for producing the hydroxy-functional precursor polymer has a disadvantage in that the chain scission results in a reduction of polymer molecular weight, as observed in Reference Example 1 of the above mentioned Kanegafuchi publication. In such a procedure, the molecular weight distribution can also be broadened.
Further, polyisobutylenes which have 2-methyl-1-propenyl end groups of the formula --HC.dbd.C(CH.sub.3).sub.2 are available commercially. However, this type of unsaturation is not amenable to hydrosilation addition reactions with SiH-functional compounds such as silanes and siloxanes. These end groups are also hard to polymerize by free radicals. Thus, the low reactivity detracts from the utility of these commercial polyisobutylenes in certain applications where copolymerization or modification with silicon-containing species is desired.
There is therefore a need for polyisobutylene polymers and oligomers which contain unsaturated groups having improved reactivity with SiH-functional compounds and/or are more reactive in free radical systems.